ISBN (International Standard Book Number) is a unique 13-digit identifier assigned to each edition of a book. It's how bookstores, libraries, and distributors identify and order books globally — essentially a barcode for the publishing industry.
ISBNs confuse more first-time authors than almost any other publishing concept. Do you need one? Where do you get one? Why does Bowker charge $125 for what's basically a number? And what's the deal with "free" ISBNs from Amazon?
Let's cut through the confusion with straight answers.
What ISBNs Actually Do
An ISBN is a unique identifier — nothing more, nothing less. It tells the global book trade: "This is a specific edition of a specific book from a specific publisher."
When a bookstore orders inventory, they use ISBNs. When a library catalogs a book, they use the ISBN. When you search for a book on any retailer's website, the system is matching ISBNs behind the scenes.
The barcode on the back of every print book? That's the ISBN converted into scannable lines.
Here's what ISBNs don't do:
- Provide copyright protection (that's automatic when you create a work)
- Guarantee bookstore placement
- Improve your Amazon rankings
- Make your book "official" in any legal sense
An ISBN is administrative infrastructure. Important? Yes. Magical? No.
Do You Actually Need an ISBN?
The honest answer: it depends on what you're doing.
You definitely need an ISBN if:
- You want your print book in bookstores (Barnes & Noble, indie stores)
- You want library distribution
- You're using IngramSpark or similar distributors
- You're selling print books professionally
You might not need an ISBN if:
- You're only selling ebooks on Amazon (they use their own ASIN system)
- You're giving away PDFs or selling directly without retail distribution
The recommendation: get an ISBN anyway. Even for ebooks. It adds legitimacy, costs nothing on platforms like Books.by, and gives you flexibility if your distribution needs change.
ISBN Costs: Free vs Paid
Here's where the industry gets frustrating. In the US, Bowker has a monopoly on ISBN sales:
| Quantity | US Cost (Bowker) | Per ISBN |
|---|---|---|
| 1 ISBN | $125 | $125.00 |
| 10 ISBNs | $295 | $29.50 |
| 100 ISBNs | $575 | $5.75 |
| 1,000 ISBNs | $1,500 | $1.50 |
Yes, that math is absurd. A single ISBN costs $125, but ten cost only $295. The pricing is designed to push authors toward bulk purchases — which makes sense if you're publishing many books, but feels predatory for first-time authors.
💡 Books.by includes free ISBNs with every $99/year subscription — unlimited ISBNs for print and ebooks, with you listed as publisher. You'll never pay Bowker a cent. Full details in our ISBN guide →
Other countries are more reasonable:
- UK: Free from Nielsen (via UK ISBN Agency)
- Canada: Free from Library and Archives Canada
- Australia: Free from Thorpe-Bowker (different from US Bowker)
- Many EU countries: Free through national agencies
If you're outside the US, check your country's ISBN agency first. You may not need to pay anything.
Free ISBNs from Platforms: The Catch
Amazon KDP offers free ISBNs. IngramSpark occasionally does too. Sounds great — what's the catch?
The catch is publisher of record. When Amazon gives you a "free" ISBN, Amazon (via Kindle Direct Publishing) is listed as your publisher. This matters because:
- That ISBN can only be used on Amazon — you can't take your book elsewhere
- Your book's bibliographic data shows Amazon as publisher, not your imprint
- Some bookstores and libraries discriminate against Amazon-published ISBNs
- If you leave Amazon, you need a new ISBN anyway
Books.by handles this differently: our free ISBNs list you (or your imprint name) as publisher of record. You own the ISBN. You can use it elsewhere. It's genuinely yours.
One ISBN Per Format: The Hidden Cost
Here's what surprises many authors: each format of your book needs its own ISBN.
- Paperback: needs an ISBN
- Hardcover: needs a different ISBN
- Ebook (if you want an ISBN for it): yet another ISBN
- Audiobook: another one
- Second edition with substantial changes: new ISBN
So that $125 for a single ISBN? If you want paperback + hardcover + ebook, you're looking at $375 minimum from Bowker — or $295 for a 10-pack with some left over.
This is why platforms with unlimited free ISBNs (like Books.by) save authors serious money over time.
How to Get an ISBN: Step by Step
Ready to get your ISBN? Here are your options:
Option 1: Use Books.by (Free, Recommended)
- Sign up for Books.by ($99/year)
- Create your book and upload your files
- ISBN is automatically assigned during publishing
- You're listed as publisher of record
Option 2: Buy from Bowker (US)
- Go to myidentifiers.com
- Create an account
- Purchase 1, 10, 100, or 1,000 ISBNs
- Assign each ISBN to a specific title/format
- Enter your metadata (title, author, publisher, etc.)
Option 3: Free from National Agencies (Non-US)
- UK: Nielsen ISBN Agency
- Canada: Library and Archives Canada
- Australia: Thorpe-Bowker
For a complete walkthrough with screenshots, see our detailed ISBN guide.
ISBN Myths Debunked
Myth: "An ISBN copyrights my book."
Reality: Copyright is automatic when you create original work. ISBNs are just identifiers.
Myth: "I need an ISBN before I can publish."
Reality: Many platforms (Books.by, KDP) assign ISBNs during the publishing process. You don't need one beforehand.
Myth: "Free ISBNs are low quality."
Reality: An ISBN is an ISBN. The number itself has no quality. What matters is who's listed as publisher of record.
Myth: "My book won't sell without an ISBN."
Reality: Amazon ebooks sell fine with just ASINs. But for print and wide distribution, yes, you need one.
Frequently Asked Questions
An ISBN (International Standard Book Number) is a unique 13-digit identifier assigned to books. Think of it like a book's fingerprint — no two editions share the same ISBN. Bookstores, libraries, and distributors use ISBNs to identify, order, and track books in their systems.
For print books you want in bookstores or libraries: yes. For ebooks sold only on Amazon: no (Amazon uses their own ASIN). For direct sales through your own website: technically no, but having one adds legitimacy and is included free with Books.by.
In the US, Bowker charges $125 for a single ISBN or $295 for 10. Many countries (UK, Canada, Australia) provide free ISBNs through government agencies. Platforms like Books.by include free ISBNs with your subscription, saving authors hundreds of dollars.
Yes, but with restrictions. Amazon's free ISBN is tied to KDP — you cannot use it elsewhere. Amazon is listed as the publisher of record. This limits your distribution options and looks less professional than owning your ISBN.
Yes. Each format (paperback, hardcover, ebook) requires its own ISBN. A second edition with significant changes also needs a new ISBN. This is why buying ISBNs in bulk from Bowker, or using a platform like Books.by with unlimited free ISBNs, makes financial sense.
ISBN-13 is the current standard (13 digits, starting with 978 or 979). ISBN-10 is the old format (10 digits) used before 2007. All new ISBNs are ISBN-13. You may see both displayed for older books, but they refer to the same title.
Yes, but with limitations. Amazon ebooks use ASINs instead. Direct sales don't technically require an ISBN. However, bookstores and libraries require ISBNs to order books. For any serious distribution or professional appearance, you need an ISBN.
The publisher of record owns the ISBN. If you buy your own ISBN from Bowker (or get one free from Books.by), you're the publisher. If you use Amazon's free ISBN, Amazon is the publisher of record. Owning your ISBN gives you more control and portability.
